Compact Polarization Beam Splitter With Multipath Interferometry
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Solution Overview
Problem
Conventional polarization beam splitters (PBS) are too large in size, limiting the data bandwidth density of optical interconnects, which is a bottleneck for future XPU development, and require improvements to meet increasing bandwidth demands.
Innovation Solution
A compact polarization beam splitter design using inverse design techniques to create an asymmetrical power splitting and multipath interferometry pattern within a 7 μm×8 μm footprint, utilizing materials with different refractive indexes to achieve high data bandwidth density by demultiplexing TE and TM optical signals efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional PBS design is used, then polarization splitting function is achieved, but physical size is too large (100 μm×8 μm)
Solution Approach 1:
The patent implements nested waveguide structures where inner waveguides are positioned within outer waveguide boundaries, creating a compact nested arrangement that reduces the overall device footprint while maintaining polarization splitting functionality through the nested geometric configuration
Solution Approach 2:
The patent transitions from conventional planar PBS geometry to a three-dimensional nested waveguide structure, utilizing vertical stacking and depth dimensions to achieve compact footprint while maintaining optical performance through volumetric space utilization
2Productivity
If PBS size is reduced to increase data bandwidth density, then area is decreased, but maintaining performance goals becomes difficult
Solution Approach 1:
The patent employs inverse design techniques to optimize waveguide parameters including refractive index profiles, waveguide dimensions, and material compositions, adjusting these parameters to achieve desired polarization splitting performance within the compact nested structure
Solution Approach 2:
The patent utilizes composite waveguide structures combining different materials with distinct refractive indices (e.g., silicon and silicon dioxide) to control optical modes and achieve precise polarization splitting while maintaining compact dimensions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compact PBS design maintains performance goals of transmission loss < -1 dB, back reflection loss < -30 dB, and polarization crosstalk loss < -20 dB, enhancing data bandwidth density and supporting future XPU demands.
Implementation Method 1
utilizing materials with different refractive indexes to achieve high data bandwidth density by demultiplexing TE and TM optical signals efficiently
Data Source
AI summary
A polarization beam splitter includes an input port, first and second output ports, and a polarization splitting region coupled between the input port and the first and second output ports. The input port is adapted to receive guided optical signals that are polarization multiplexed, including a transverse electric (TE) optical signal and a transverse magnetic (TM) optical signal. The polarization splitting region includes a pattern of at least two materials having different refractive indexes. The pattern is shaped to demultiplex the TE and TM optical signals by directing a first power majority of the TE optical signal received at the input port to the second output port via asymmetrical power splitting while directing a second power majority of the TM optical signal received at the input port to the first output port via multipath interferometry.